Standardization organizations such as OASIS (OpenADR) and ZigBee are promoting automated processing systems for reducing power consumption during critical periods of peak power demand, in which a DRAS (a demand response automated server) located at an electric power company side transmits a power consumption reduction signal (a DR signal) to an EMS (energy managing system) installed at a customer side.
In connection with the system, a method has conventionally been proposed, in which determination is made to how equipment of each customer should be controlled, on the basis of indicators such as comfort and an electric power rate, and a daily load curve is calculated to schedule the total amount of demand to be restrained. In this technique, a method of changing a plan on the basis of each customer's activity of a particular day has not been proposed. Further, a method of calculating reducible reserve power (reserve capacity) of each customer when a plan is changed has not been proposed.